1. Field of the Invention
The invention relates to a heat dissipating device, more particularly to a heat dissipating module for a heat generating electronic component, such as a central processing unit of a notebook computer.
2. Description of the Related Art
UPGA-type central processing units for new generation notebook computers have very stringent heat dissipating and circuit board mounting requirements. FIG. 1 illustrates a conventional heat dissipating module for a central processing unit 1 of a notebook computer. As shown, a computer main board 2 has a top side 21 provided with an integrated circuit socket 22 for establishing electrical connection with the central processing unit 1, and a mounting frame 23 that surrounds the socket 22. The heat dissipating module includes a heat dissipating plate 3, having an area larger than that of the frame 23, which is used to cover an open top of the frame 23 and to contact the central processing unit 1. The heat dissipating plate 3 has four corner portions formed with plate fastener holes 30. The frame 23 is formed with frame fastener holes 230 that correspond respectively with the plate fastener holes 30. As shown in FIG. 2, the main board 2 is formed with board fastener holes 24 that are aligned with the frame fastener holes 230. The heat dissipating module further includes a back plate 4 disposed below the main board 2 and formed with plate fastener holes 40 that correspond respectively with the board fastener holes 24. Four fastening bolts 41 are extended through aligned ones of the fastener holes 40, 24, 230, 30 from the bottom side of the main board 2, and engage threadedly a corresponding nut 42 above the heat dissipating plate 3, thereby fastening the back plate 4 and the heat dissipating plate 3 on the main board 2.
Because of the need to use fastening bolts 41 that are extended from the bottom side of the main board 2 and that engage corresponding nuts 42 above the heat dissipating plate 3, fastening of the back plate 4 and the heat dissipating plate 3 on the main board 2 not only requires the use of tools, but is also inconvenient and time-consuming to conduct. Moreover, in case an excessively large force was applied during the fastening operation, deformation of the main board 2 is likely to occur. Furthermore, while the mounting frame 23 around the socket 22 facilitates stable fastening of the heat dissipating plate 3 on the main board 2, the presence of the frame 23 increases the height and cost of the main board 2.